But years later, in 2014, a U.S. study found that almost half of the children with ASD had average or above average intelligence, that is, an IQ score above 85. Less than a third of the children with autism had intellectual disability, and 23% had IQ scores in the "borderline range" from 71 to 85.
Older epidemiological studies suggested that the IQ-related spectrum tends to be skewed to the left, i.e., a larger proportion of individuals with ASD have below average intelligence, while only few individuals with ASD may have an IQ above average.
Although up to 70 per cent of individuals with autism have an intellectual disability, some people with the disorder have relatively well-preserved, or even higher than average, non-verbal intelligence, the team says. Autism is a developmental disability that can cause significant language and speech difficulties.
About 70% of autistic people have an intellectual disability, which means they have an IQ lower than 70. The remaining 30% have intelligence that ranges from average to gifted. Autism and intelligence are two separate characteristics. A person can be autistic with any level of intelligence.
Savant syndrome is a rare, but extraordinary, condition in which persons with serious mental disabilities, including autistic disorder, have some 'island of genius' which stands in marked, incongruous contrast to overall handicap.
Those with Asperger's syndrome, in contrast, must by definition have suffered no cognitive delay during their first 3 years of life. This means that they will usually have at least a “normal” IQ. In some cases, their IQ may be very high, even in the genius range. There are, however, different kinds of smarts.
Due to its lower prevalence in females, autism was always thought to have a maternal inheritance component. However, research also suggests that the rarer variants associated with autism are mostly inherited from the father.
Advances in diagnostic capabilities and greater understanding and awareness of autism spectrum disorder seem to be largely driving the increase, the Rutgers researchers said. But there's probably more to the story: Genetic factors, and perhaps some environmental ones, too, might also be contributing to the trend.
A common question after an autism diagnosis is what is the cause of autism. We know that there's no one cause of autism. Research suggests that autism develops from a combination of genetic and nongenetic, or environmental, influences. These influences appear to increase the risk that a child will develop autism.
It is estimated that 1 in 100 people in Australia have Autism. In 2018 there were 205,200 Australians with Autism, a 25.1% increase from the 164,000 in 2015 (Source: ABS SDAC 2018– Autism in Australia). This means that if you have Autism you are not alone.
There are many different factors that have been identified that may make a child more likely to have ASD, including environmental, biologic, and genetic factors.
ADHD is not on the autism spectrum, but they have some of the same symptoms. And having one of these conditions increases the chances of having the other. Experts have changed the way they think about how autism and ADHD are related.
Main signs of autism
finding it hard to understand what others are thinking or feeling. getting very anxious about social situations. finding it hard to make friends or preferring to be on your own.
Autism Prevalence
31% of children with ASD have an intellectual disability (intelligence quotient [IQ] <70), 25% are in the borderline range (IQ 71–85), and 44% have IQ scores in the average to above average range (i.e., IQ >85).
About 70% of children with ASD have a non-verbal IQ below 70. Of these, 50% have a non-verbal IQ below 50. Overall, up to 50% of people with "severe learning difficulties" have an ASD. Read more about the symptoms of ASD.
Although both OCD and ASD have similar symptoms, they are different conditions. OCD is a mental health disorder, whereas ASD is a developmental condition. ASD is a condition that a person is born with. OCD can develop during a person's lifetime.
Is bipolar disorder on the autism spectrum? No. Bipolar disorder is not part of the autism spectrum, though an unusually large number of people with bipolar disorder are also autistic (and vice versa).
The symptoms of Asperger's Syndrome are now included in a condition called Autism Spectrum Disorder (ASD). ASD is now the name used for a wide range of autism-like disorders. Some providers may still use the term Asperger's Syndrome, but others will say “ASD – without intellectual or language impairment.”
Genetics. Genetic factors may be the most significant cause of autism. Early studies of twins had estimated heritability to be over 90%, meaning that genetics explains over 90% of whether a child will develop autism. This may be an overestimation, as later twin studies estimate the heritability at between 60 and 90%.
Autism is not an illness
It's something you're born with. Signs of autism might be noticed when you're very young, or not until you're older. If you're autistic, you're autistic your whole life.
Common life experiences such as facing the death of a loved one, failed romantic relationships, employment problems, etc., can exacerbate autism symptoms in adults. In these cases, autism symptoms can get worse with age, but not necessarily due to the disorder neurologically worsening.
The rates of autism are also rising because of changes in the way it's diagnosed. Currently, this is by measuring a child against known developmental benchmarks. One common assessment method is an 'Autism Diagnostic Interview – Revised': an interview between a trained assessor and the primary caregiver.